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4-5” reflector recommendation

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#26 Jon Isaacs

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Posted 16 June 2019 - 10:28 AM

Long time ago I owned a Vixen 4" f/10 achromat made in Japan.

 

Never liked the strong blue fringe around moon and the planets.

 

I shortly owned a 5" Meade ETX UHTC Maksutov. Features on planets really started to show.  No comparison to a crappy false colour ladden 4" achromat.

 

And I wish to add: It was impossible to observe Mars with the Vixen 4" f/10 achromat. Post #175 and the link therein that confirms my experience: https://www.cloudyni...teed-fan/page-7

 

I would rather have a decent 4 inch F/10 achromat than the Starmax 127mm I that I owned for a while.  Viewing the planets with a moderate focal length achromat can be done with color filters,. CO's and poor optics cannot be fixed.  

 

Jon



#27 Magnetic Field

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Posted 16 June 2019 - 10:56 AM

I would rather have a decent 4 inch F/10 achromat than the Starmax 127mm I that I owned for a while.  Viewing the planets with a moderate focal length achromat can be done with color filters,. CO's and poor optics cannot be fixed.  

 

Jon

But the ETX 125 was so much better on planets than a made in Japan Vixen achromat.

 

The CO is a mood point and the fear is completely irrational.***

 

An achromat is just an outdated design. And not being able to observe Mars is a severe flaw (I would hate to use special filters to fake a false colour free view).

 

 

***This must be the reason why there is no professional observatories in operation world wide or in space that use refractors. And before someone now tells me that there is an observatory with a refractor and that his grandfather is 99 years of age and smokes 60 Marlboros a day, please this is not the point. 


Edited by Magnetic Field, 16 June 2019 - 10:58 AM.


#28 aeajr

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Posted 16 June 2019 - 11:09 AM

I think there is an implied limit on funds in the OP's original post.

 

This rules out a refractor. An achromat should be a thing of the past especially (as the OP requires) for moon and (lesser degree) double stars.

 

If money is not an issue OP how about a 90mm ED apochromat? Or even a 4" ED apo? 

 

(In the past I often recommended the Vixen VMC 110L,  but I cannot recommend that crap any more and thread will follow in the next few weeks).

When someone says a "quality" scope there is no implication of a limited budget.   Quite the contrary, there is a suggestion that price is not an issue. 

 

The OP never provided a budget so we know nothing about his financial goals.  And he has two other scopes so we are working with someone who knows something about astronomy and equipment.  Probably has a good collection of eyepieces and other accessories. 

 

I happen to really like achromats for visual.  I have two and enjoy them very much.  A little CA doesn't bother me and it certainly won't bother the children for whom the scope is targeted.  But if he has the funds, an APO refractor would be an excellent choice. 

 

Not everyone needs an APO.  I certainly don't. 

 

I have a tabletop Newtonian, an Orion SkyScanner 100.   It is a fun little scope that is used more as a loaner scope.  When I use it I rarely use it on the tabletop. I take the OTA off the tabletop mount and put it on the tripod of my achro refractor.  Much more convenient. 



#29 Magnetic Field

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Posted 16 June 2019 - 11:20 AM

When someone says a "quality" scope there is no implication of a limited budget.   Quite the contrary, there is a suggestion that price is not an issue. 

 

The OP never provided a budget so we know nothing about his financial goals.  And he has two other scopes so we are working with someone who knows something about astronomy and equipment.  Probably has a good collection of eyepieces and other accessories. 

 

I happen to really like achromats for visual.  I have two and enjoy them very much.  A little CA doesn't bother me and it certainly won't bother the children for whom the scope is targeted.  But if he has the funds, an APO refractor would be an excellent choice. 

 

Not everyone needs an APO.  I certainly don't. 

 

I have a tabletop Newtonian, an Orion SkyScanner 100.   It is a fun little scope that is used more as a loaner scope.  When I use it I rarely use it on the tabletop. I take the OTA off the tabletop mount and put it on the tripod of my achro refractor.  Much more convenient. 

If the OP has really no limit a 4" apochoromat is a no brainer.

 

A 4" apo is probably the safest bet: no collimation issues, good cool down time and can also be used for deep sky observing at low magnifications.



#30 clearwaterdave

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Posted 16 June 2019 - 11:55 AM

How is a 4" apo a "no brainer" when the OP specificly asked about a reflector? The OP has other scopes and seems to have some idea of what he's lookin for.,What scope you think would do a better job for doubles or planets is not what he asked about.,

  If you have used and liked a 4-5" reflector of any type and you want to share your experience here that would be helpful to the OP.,waytogo.gif


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#31 Magnetic Field

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Posted 16 June 2019 - 12:21 PM

How is a 4" apo a "no brainer" when the OP specificly asked about a reflector? The OP has other scopes and seems to have some idea of what he's lookin for.,What scope you think would do a better job for doubles or planets is not what he asked about.,

  If you have used and liked a 4-5" reflector of any type and you want to share your experience here that would be helpful to the OP.,waytogo.gif

Fair point he didn't ask for a refractor.

 

No one stops the OP from buying the $199 Onesky.

 

But fact remains: if he is not constrained by money and does not mind spending it: a 4" apchromat is just the better choice. Yes the 4" apo is an expensive choice. A Meade ETX125 would  be a cheaper option for the moon though.

 

Does anyone here expect good optics from a $199 reflector? It can only be hit and miss. But the OP said he wants good optics.


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#32 clearwaterdave

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Posted 16 June 2019 - 12:34 PM

I have had the OS up next to a 102ed and "to my eyes" the views are too similar for me to say either one was "better".,And there are many many very happy OS owners.,So yes.,you can expect a quality reflector for $200.,That's the no brainer.,and the OS isn't the only one.,there are a few good quality 5" reflectors out there for $200.,YOMV.,



#33 Magnetic Field

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Posted 16 June 2019 - 12:56 PM

I have had the OS up next to a 102ed and "to my eyes" the views are too similar for me to say either one was "better".,And there are many many very happy OS owners.,So yes.,you can expect a quality reflector for $200.,That's the no brainer.,and the OS isn't the only one.,there are a few good quality 5" reflectors out there for $200.,YOMV.,

I have now come to realise a Meade ETX-125 would be the best choice for the OP.

 

No one needs a goto for finding the moon but it will be very handy once he screwed in a high mag eyepiece. He then can focus his mind on observing the moon at high powers without having to manually track the moon.

 

I just hate my Vixen Mini Porta for high powered views of the planets. Manually tracking it in altitude and azimuth drives me crazy and totally detracts from actually observing the planet.

 

The OP wants to take part in a lunar observing programe: "and perhaps do the AL lunar observing program".

 

This requires more than just glancing at the moon.

 

The only drawback: after a few years the Meade goto junk plastic electronics will stop working.



#34 Jon Isaacs

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Posted 16 June 2019 - 01:13 PM

But the ETX 125 was so much better on planets than a made in Japan Vixen achromat.

 

The CO is a mood point and the fear is completely irrational.***

 

An achromat is just an outdated design. And not being able to observe Mars is a severe flaw (I would hate to use special filters to fake a false colour free view).

 

 

***This must be the reason why there is no professional observatories in operation world wide or in space that use refractors. And before someone now tells me that there is an observatory with a refractor and that his grandfather is 99 years of age and smokes 60 Marlboros a day, please this is not the point. 

 

I have experimented by adding a CO of 40% to a 120 mm  apo refractor. The analysis said it does significant damage, visually, that damage is easily seen. That refractor was way better, particularly on unequal doubles, than a similar aperture Mak.

 

We are not discussing large aperture scopes, we are discussing small scopes where the CO affects the view.

 

At this point, we are not helping the original poster with this discussion.

 

Jon


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#35 Mick Christopher

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Posted 16 June 2019 - 01:25 PM

Thank you again for all the great responses. I’m always pleasantly surprised at the information you guys have and your experience. Yes, optics are my primary concern for the scope, but I haven’t really read one bad review concerning them so I think the OneSky is what I’ll go with. I have a pretty large back deck with a decent view to the south so it will be easy to track the moon every night, even if only for a few minutes. Concerning refractors: the truth is I have little experience with them (I know they’re not hard to figure out) and my comfort level, if you will, is with Dobsonian type reflectors. I have a neighbor down the road who has a 4” Takahashi (I think), and the views through it are really something else. Then he told me the price tag and my mind went to how how big of a Renegade or Teeter I could get for the same price. Plus someone told me that owning a refractor will lead you down to the perilous and very expensive road of astrophotography.
The reason I don’t put the 8” out on the back deck is that I use it specifically for planetary viewing now. I have it in the garage ready to load up for a quick drive into the foothills next to the house. The view is better and I get away from all the house and street lights. At f/7 that 8” gives just wonderful views of the planets. I was also able to complete the AL double star program with. If you haven’t looked at that program, I recommend it as it was one of my favorites to do. The 8” was the first scope I ever owned and I had to rebuild it out of disassembled parts, which I found at a flea market. That was a journey, let me tell me you. But now it’s dialed in with a great mirror and I’ll have it forever.
And with the 10”: that’s my deep-sky, dark site, fall into the heavens scope. I try to get out there at least once, if not twice, a week. It too has great mirror and makes it hard for me to financially justify a larger scope given there’s so much to see with it.
Back to the OneSky. Hopefully it will be what I’m looking for. I have perfect cover and place for it, it won’t get dirty, and when I’m out enjoying the late evening and want a quick peak, it’ll be right there.
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#36 dmgriff

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Posted 16 June 2019 - 01:49 PM

The collaspible OneSky works well enough on a Twilight I mount for me. The focuser is the main fault. 

 

Enjoy luna....

 

Good viewing,

 

Dave


Edited by dmgriff, 16 June 2019 - 01:52 PM.

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#37 Jon Isaacs

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Posted 16 June 2019 - 02:18 PM

Concerning refractors: the truth is I have little experience with them (I know they’re not hard to figure out) and my comfort level, if you will, is with Dobsonian type reflectors. I have a neighbor down the road who has a 4” Takahashi (I think), and the views through it are really something else. Then he told me the price tag and my mind went to how how big of a Renegade or Teeter I could get for the same price.

 

 

To get those refractor views, you do not need a Takahashi or other high end refractor. An Orion ED-100 or Skywatcher ED-100 will provide very similar views for a fraction of the cost. I see used ED-100s in the $400 range, I have seen them for $300.  You will need a mount.

 

Certainly the one sky offers a lot of scope for $200. The focuser is not so great, the mount has the same issues any tabletop mount has.  And for a $200 scope, it's probably about as good as it gets. That's why it gets good ratings.

 

But if you want to invest more, you can get a scope that will be considerably more capable. This is a search many of us have embarked upon.  Sooner or later it usually ends up with an apo/Ed refractor of some sort.

 

Jon


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#38 KerryR

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Posted 16 June 2019 - 03:06 PM

One of my all-time favorite 4ish inch scopes is the Orion XT4.5, mentioned by Dave and Ed earlier. It's a very nicely engineered and accessorized product, and provides sharp high power views with very minimal focus wiggles and immediate dampening times. The long focal length makes the scope forgiving of the somewhat imprecise focuser, which works quite well. It's also very easy on simple eyepieces, which is handy. It's not a do-all scope, owing to the focal length and 1.25" ep limitation, but it's still capable of providing pleasant low power views, yet shines at moderate and high powers. Add a 5 gallon bucket, inverted, as a "chair" (which can pull double duty as a caddy for charts, ep case, and binos) , and the scope works well for adults without the need to raise the scope on a platform.


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#39 Mick Christopher

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Posted 16 June 2019 - 04:26 PM

The collaspible OneSky works well enough on a Twilight I mount for me. The focuser is the main fault. 

 

Enjoy luna....

 

Good viewing,

 

Dave

I read that wrapping the focuser threads with a layer or two of silicone tape helps the focuser issue.



#40 clearwaterdave

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Posted 16 June 2019 - 07:40 PM

Mick C. Have you seen the thread about the OS in the beginners forum.,lots of info an tips.,good cloudy nights reading if your lookin at this scope.,cheers.,


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#41 Mick Christopher

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Posted 17 June 2019 - 08:41 AM

Mick C. Have you seen the thread about the OS in the beginners forum.,lots of info an tips.,good cloudy nights reading if your lookin at this scope.,cheers.,

I read through it with my morning coffee, thanks for the tip!



#42 aeajr

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Posted 17 June 2019 - 09:19 AM

Mick,

 

Best of luck with your new telescope.  Let us know how it works out for you and the kids.


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#43 Mick Christopher

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Posted 17 June 2019 - 10:00 AM

Mick,

 

Best of luck with your new telescope.  Let us know how it works out for you and the kids.

Will do, and thanks for all your info!



#44 aeajr

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Posted 17 June 2019 - 10:33 AM

How old are the kids?

 

Since you plan to use that scope for the Moon and doubles, do you plan to stay in the lower power ranges, say under 100X or will you be pushing up to things like the double double?   I don't normally think of a shorter FL refractor as a double star scope but, of course, if you pick your targets properly, it can do just fine. I presume you have a 2X or 3X barlow.

 

I do a fair amount of outreach and often show globular clusters which I describe to the kids as stellar fireworks.  They really like that idea.   I find that if you give the kids something they can relate to, like fireworks, they get much more interested.

 

Some of the open clusters can take on a similar look. If you have a good view of the southern horizon, M6 and M7 would be wonderful.  The double cluster, for example, could be described as side by side stellar fireworks explosions frozen in the sky.   The One Sky should be very good for open clusters. 

 

Open clusters by the Season

https://www.skyandte...-by-the-season/

 

Messier with Binoculars - Should also be great target list
https://www.astrolea...s/binomesa.html

 

Just some thoughts.  



#45 Mick Christopher

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Posted 17 June 2019 - 11:42 AM

How old are the kids?

 

Since you plan to use that scope for the Moon and doubles, do you plan to stay in the lower power ranges, say under 100X or will you be pushing up to things like the double double?   I don't normally think of a shorter FL refractor as a double star scope but, of course, if you pick your targets properly, it can do just fine. I presume you have a 2X or 3X barlow.

 

I do a fair amount of outreach and often show globular clusters which I describe to the kids as stellar fireworks.  They really like that idea.   I find that if you give the kids something they can relate to, like fireworks, they get much more interested.

 

Some of the open clusters can take on a similar look. If you have a good view of the southern horizon, M6 and M7 would be wonderful.  The double cluster, for example, could be described as side by side stellar fireworks explosions frozen in the sky.   The One Sky should be very good for open clusters. 

 

Open clusters by the Season

https://www.skyandte...-by-the-season/

 

Messier with Binoculars - Should also be great target list
https://www.astrolea...s/binomesa.html

 

Just some thoughts.  

I’ll see how much magnification I can push with but I don’t expect to go far. Like I said it will be mostly for lunar observing and any notable events/objects that are up. My son has seen the gamut of objects through the 10” but being only six, the moon and planets are where it’s at for him. Baby girl is only a year but her time will come. I’m interested to see how the planets will look through the OneSky though. I hope to order it tonight so we’ll find out here shortly.


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#46 Binojunky

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Posted 18 June 2019 - 09:42 AM

If the OP can handle the extra size and cost the Orion XT6"F8 is a fine scope, I picked mine up last years for $300 Canadian brand new shipped to my door, take it out in two pieces, plonk it on the ground and away you go, D.


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